/**
 * Created with IntelliJ IDEA.
 * Description:
 * User: 86183
 * Date: 2022-11-02
 * Time: 14:36
 */
public class SingleLinkedList {
    static class ListNode {
        int val;
        ListNode head;
        ListNode next;
        ListNode(int val) {
            this.val = val;
        }
    }
    public ListNode head;
    //头插法
    public void addFirst(int data){
     ListNode node = new ListNode(data);
        if(head == null){
            head = node;
            return;
        }
        node.next = head;
        head = node;
    }
//    //尾插法
    public void addLast(int data){
        ListNode node = new ListNode(data);
        if(head == null){
            head = node;
            return;
        }
        ListNode cur = head;
        while (cur.next != null){
            cur = cur.next;
        }
        cur.next = node;
    }
//    //任意位置插入,第一个数据节点为0号下标
    public void addIndex(int index,int data) {
        if(index < 0||index > size()){
            throw new IndexBoundWrongful("index位置不合法");
        }
        if(index == 0){
            addFirst(data);
            return;
        }
        if(index == size()){
            addLast(data);
            return;
        }
        ListNode cur = findeindex(index);
        ListNode node = new ListNode(data);
        node.next = cur.next;
        cur.next = node;
    }

    private ListNode findeindex(int index) {
        int count =index-1;
        ListNode cur = head;
        while (count != 0){
            cur = cur.next;
            count--;
        }
        return cur;
    }

    //    //查找是否包含关键字key是否在单链表当中
    public boolean contains(int key){
        ListNode cur = head;
        while (cur != null){
            if(cur.val == key){
                return true;
            }
            cur = cur.next;
        }
        return false;
    }
    //删除第一次出现关键字为key的节点
    public void remove(int key){
        if(head == null){
            System.out.println("该链表为空");
            return;
        }
        if(head.val == key){
            head = head.next;
            return;
        }
        ListNode cur = findKey(key);
        if(cur == null){
            System.out.println("该值不存在");
            return;
        }
        cur.next = cur.next.next;

    }

    private ListNode findKey(int key) {
        ListNode cur = head;
        while (cur.next!= null){
            if(cur.next.val == key){
                return cur;
            }
            cur =cur.next;
        }
        return null;
    }

    //    //删除所有值为key的节点
    public void removeAllKey(int key){
       if(this.head == null){
           return;
       }
       ListNode cur = head.next;
       ListNode prev = head;
       while (cur != null){
           if(cur.val == key){
               prev.next = cur.next;
           }else {
               prev= prev.next;
           }
           cur = cur.next;
       }
       if(head.val == key){
           head = head.next;
       }
    }
//    //得到单链表的长度
    public int size(){
        int count = 0;
        ListNode cur = head;
        while (cur != null){
            cur =cur.next;
            count++;
        }
        return  count;
    }
    public void display(){
        ListNode cur = head;
        while (cur != null){
            System.out.print(cur.val+" ");
            cur = cur.next;
        }
    }
    public void clear(){
        this.head = null;

    }
}
